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LOS ANGELES, California (AP) -- In March, NASA launched an experimental jet that reached a record-setting speed of about 5,000 mph (8,050 kph). Now researchers want to leave that milestone in the dust. NASA's third and last X-43A "scramjet" was set to streak over the Pacific Ocean on Monday at 7,000 mph (11,260 kph) for 10 or 11 seconds -- or 10 times the speed of sound.

The first X-43A flight failed in June 2001 when the booster rocket used to accelerate it to flight speed veered off course and had to be destroyed.

The second flight in March was a success, reaching Mach 6.83 -- nearly 5,000 mph -- and setting a new world speed record for a plane powered by an air-breathing engine.

The last hypersonic X-43A will try, weather permitting, to break that record by making its advanced supersonic combustion ramjet perform at a level that can't even be tested on the ground, project officials said Wednesday from NASA's Dryden Flight Research Center at Edwards Air Force Base, California.

"What we're trying to do is really get to the reality of flight -- find out what does work, what doesn't work. So there is risk in this program," said Vince Rausch, Hyper-X program manager at NASA's Langley Research Center in Virginia. "We fully anticipate that we've reduced that risk to acceptable levels but you never are sure, especially in doing something for the first time, going Mach 10, until we actually fly."

Just 12 feet (3.7 meters) long and 5 feet (1.5 meters) wide, the unmanned X-43A is mounted on the nose of a Pegasus rocket that will be carried aloft to 40,000 feet (12,200 meters) by NASA's B-52 research aircraft and released. The Pegasus rocket will ignite and carry the X-43A to an altitude of 110,000 feet (33,528 meters) and a speed of about Mach 10, then release it for its brief powered flight. The X-43A will then become a glider and perform maneuvers until it splashes down into the ocean. That will be the end of the X-43A project, which has cost more than $230 million and has no immediate follow-on program.

"I have mixed emotions about this mission," said Joel Sitz, project manager for X-43A flight research at Dryden. "I'm very excited about next week. I'm also a little bit sad about seeing the end of the program. It's like watching your son go off to college." Scramjet technology may be used in developing hypersonic missiles and airplanes or reusable space launch vehicles, with a potential for offering speeds of at least Mach 15.

Unlike rockets, scramjets wouldn't have to carry heavy oxidizer necessary to allow fuel to burn because they can scoop oxygen out of the atmosphere.



Archived topic from Anythingforums, old topic ID:1312, old post ID:16750

Woah, mack 10! 7 was the record last I heard but I'm not sure if it was for a jet or not. I wonder how they handle the G force though, some serious gear must be required for the pilot.

Archived topic from Anythingforums, old topic ID:1312, old post ID:16765

yeah, they wear g-suits, that regulate the forces on the body.

Archived topic from Anythingforums, old topic ID:1312, old post ID:16767

update:

http://news.bbc.co.uk/2/hi/science/nature/4018117.stm

Nasa flew an unmanned experimental jet on Tuesday to a speed that was in excess of nine times the speed of sound - a world record.
The X-43A - a supersonic combustion ramjet (scramjet) - was released on its test run from beneath a bomber's wing.

The 3.7m-long aircraft had already set a world best for an "air breathing" jet of Mach 6.83 - nearly seven times the speed of sound - on a flight in March.

Preliminary data confirming the success came through in real-time.

Scramjets are being developed in a number of countries as an alternative propulsion system to rockets.

Future applications could include hypersonic missiles and airplanes, and reusable single- or two-stage-to-orbit space launchers.

"The US space agency's goal has been to get to space more routinely and in a safer fashion," Joel Sitz, project manager for the X-43A, told the BBC News website.

Some commentators have even speculated that scramjets could one day be used on passenger airliners, dramatically cutting long-haul journey times.


The latest flight of the X-43A was supposed to have taken place on Monday. But pre-flight avionics checks overran and the vehicle, which holds the world speed record for an "air-breathing" jet, was stood down for 24 hours.

On Tuesday, the flight went ahead as planned over the Naval Air Warfare Center Weapons Division Sea Range, which is just to the northwest of Los Angeles.

The X-43A was positioned on the nose of a Pegasus booster rocket and attached to the underside of a B52B aircraft's wing.

The paired X-43A and booster were then lifted to an altitude of 12km (40,000ft) and released; the booster taking the scramjet higher still.

Separation and onward flight of the scramjet was designed to take place at an altitude of about 33.5km (110,000ft).

Engineers expected the X-43A to travel about 1,370km (850 miles) before plunging into the Pacific.

Scramjets achieve their fantastic speeds by burning a hydrogen propellant but without the need to carry heavy oxygen tanks as rockets must.

They take their oxygen from the air, which is naturally compressed by the forward speed of the vehicle and the shape of the vehicle's inlet.

Unlike a conventional jet engine, there are no rotating blades to compress the air.

Getting fuel to ignite in a supersonic air stream has been likened to "striking a match in a hurricane"; so, successful combustion relies on controlling temperature and pressure within the engine.

The concept should allow for greater payload capacity at reduced cost.



Archived topic from Anythingforums, old topic ID:1312, old post ID:16812